A current liquid crystal display usually employs a number of light emitting diodes (LEDs) as a backlight module. However, the LED is an electroluminescent device and wastes a lot of energy for a long time use. Nature sunlight is environmental free energy and should be considered being used as a backlight resource of liquid crystal display. However, solar energy is not available at night or in cloudy days and the color temperature of sunlight is 6000K, far from a color temperature range of normal backlight resource from 10000K to 20000K, which influences a display effect.
Therefore, it is desirable to provide a means which can solve the above-mentioned problems.